For radio communication, wireless local area network (LAN) standards such as IEEE802.11 have been set. As the wireless LAN standards, higher standards that support higher communication rates using the same frequency band tend to be set in sequence. For example, a higher standard than IEEE802.11a, IEEE802.11n, has already been set.
In the case of radio communication including communication conforming to a wireless LAN standard as mentioned above, it is necessary to avoid collisions of communication in the same frequency band. To this end, for example, in IEEE802.11, a Request To Send/Clear To Send (RTS/CTS) mechanism has been introduced. In this mechanism, a radio communication device that will perform data transmission performs communication for ensuring communication time with another nearby radio communication device before data transmission.
When a higher standard and a lower standard such as IEEE802.11a and IEEE802.11n are permitted to coexist in the same frequency band, for example, communication for the RTS/CTS needs to be performed according to the lower standard so that a radio communication device corresponding only to the lower standard can also receive the RTS/CTS. As a result, even during transmission and reception according to the higher standard, low-speed communication is performed according to the lower standard and overhead of the higher standard increases, and thus full performance may not be exhibited.
In Patent Literature 1 below, an example of technology for avoiding a communication collision without using a sequence such as the RTS/CTS in an environment in which two communication schemes of higher and lower standards coexist is disclosed.
For example, in wireless LAN standards, a standard that is referred to as IEEE802.11ac and supports a further higher communication rate has recently been set above IEEE802.11a and IEEE802.11n. In this way, coexistence of three communication schemes constituting classes in radio communication is being realized.